A large-scale electricity storage system with secondary batteries is expected to be utilized in applications such as a suppression of power generation fluctuation which utilizes natural energies like solar light and wind power, a suppression of a power demand fluctuation, and a peak shift. In order to construct such a large-scale electricity storage system, cases in which plural batteries individually controllable for charge/discharge power, etc. (sub battery system: hereinafter, simply referred to as “batteries”), are utilized in combination will increase. According to such a system constructed by plural batteries, it is important how to distribute, to the individual batteries that construct the electricity storage system, an instruction value for charge/discharge power, etc., relative to the whole electricity storage system.